U.S. Pat. No. 3,428,019 discloses a streamer-type drop marker that has been successfully used for a number of years. Such markers are often dropped from low flying aircraft to visually mark the ground surface passed over by the aircraft. Such markers are used extensively by "crop duster" type planes to mark the field location of a spray pattern in order to avoid gaps or overlap of spray swaths.
Streamer type drop markers are typically provided in banded bundles and may be placed for dispensing within an apparatus such as that shown in U.S. Pat. No. 3,470,846. This patent discloses a remotely controlled dispenser for drop markers of the type shown in the 3,428,019 patent. The dispenser includes an elongated chute for receiving a stack of the drop markers. The stack is biased toward a dispensing end by air pressure exerted through a hole at the leading end of the chute. The rearward drop marker of the stack is held by rigid card stops that project into the rearward path of the rearwardly biased stack. A solenoid plunger is situated adjacent to the card stops and is selectively operated by a solenoid energizer to selectively eject the successive drop markers from the dispenser chute. The markers are ejected along a path that is transverse to the longitudinal orientation of the stack.
A problem that has been realized with the form of drop marker shown in U.S. Pat. No. 3,428,019 and the aircraft mounted dispenser shown in U.S. Pat. No. 3,470,846, is in loading the drop markers into the dispenser chute. Reloading is a slow, multi-step process which is unforgiving of operator error and which takes place in less than optimum conditions and often under strong pressure to get the job done quickly. The reloading must often be done with the aircraft engine running. The propeller blast greatly increases the complexity of the task of manipulating large numbers of the drop markers. The reloading sequence with an airplane mounted dispenser as necessitated by the above apparatus and marker designs is as follows:
1. The aircraft pulls into position and the engine speed is set at idle.
2. An assistant carries a supply of drop markers to the dispenser, which is typically mounted on the aircraft wing. (The marker supply usually consists of an open box of markers.)
3. The dispenser lid is opened, with care being taken that the propeller blast does not blow away any possible remaining markers within the dispenser chute.
4. Bundles of markers are then removed from the case and are inserted into the dispenser chute. A paper band holding each bundle must be removed either before or after insertion of the markers into the dispenser. The tissue paper streamers, which are an integral part of the markers, must be kept under positive control at all times during the reloading process or the streamers will unfurl in the prop blast and be rendered unusable.
5. The paper bands which have been removed must be controlled and temporarily stored for later disposal, or they will be blown away.
6. If the case of markers or a bundle of markers happens to be accidentally dropped, many of the markers may be broken, blown about, and rendered unusable. These destroyed markers must then be collected for disposal.
7. When a sufficient quantity of bundles have been inserted into the dispenser, the lid is closed and fasteners for securing the lid are latched. The dispenser is now loaded and ready for use.
The total time spent reloading while the aircraft is parked and waiting may average as much as three to four minutes. This represents a considerable expenditure of time and fuel. It is not convenient or efficient to stop the engine during the reloading period as this would still further increase the "down time" and result in little, if any, savings of fuel due to the increased amounts of energy required to restart the engine.
It therefore becomes desirable to minimize the amount of time and effort required to reload drop marker dispensers.